Chapter 5

Fischer Assay Histograms of Oil Shale 

Drill Cores and Cuttings from the Uinta 

Basin, Utah and Colorado

By Jesse G. Self, Michael E. Brownfield, Ronald C. Johnson, and 

Tracey J. Mercier

Chapter 5 of 7

Oil Shale Resources of the Uinta Basin, Utah and Colorado 

By U.S. Geological Survey Oil Shale Assessment Team

U.S. Geological Survey Digital Data Series DDS–69–BB

U.S. Department of the Interior

U.S. Geological Survey

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Volume Title Page
U.S. Department of the Interior

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2010

For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, 

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reproduce any copyrighted materials contained within this report.

Suggested citation:

Self, J.G., Brownfield, M.E., Johnson, R.C., and Mercier, T.J., 2010, Fischer assay histograms of oil shale drill cores 

and cuttings from the Uinta basin, Utah and Colorado: U.S. Geological Survey Digital Data Series DDS–69–BB, 

chp. 5, 8 p.
iii

Contents

Introduction.....................................................................................................................................................1

CD–ROM..........................................................................................................................................................1

Oil-Yield Histograms ......................................................................................................................................4

References Cited............................................................................................................................................8

Figures

1. Geologic map of the Uinta and Piceance Basins, northeastern Utah and 

northwestern Colorado, showing Upper Cretaceous and Lower Tertiary units ................2

2. Tertiary stratigraphic column for the Uinta Basin, northeastern Utah and 

northwestern Colorado, showing the Wasatch, North Horn, Green River, 

Duchesne River, and Uinta Formations and associated members.......................................3

3. Part of the histogram plot showing Fischer assay oil-yield data for borehole 

U0020; with sampling from the Parachute Creek Member of the Green 

River Formation in the Uinta Basin, northeastern Utah and northwestern Colorado .......7

Plate

1. Locations of drill holes in the Uinta Basin, northeastern Utah and 

northwestern Colorado........................................................................................................... link

Tables

1. Names and definitions for the column headers for the Utah oil shale borehole

information spreadsheet (UT_Borehole.xlsx)..........................................................................5

2. Names and definitions for the column headers for the Fischer assay data 

spreadsheet (UT_Oil_Shale_Assays.xlsx) ......................................................................................6
Introduction

This CD–ROM chapter presents oil-yield histograms 

of samples of cores and cuttings from exploration drill holes 

in the Eocene Green River Formation in the Uinta Basin of 

northeastern Utah and northwestern Colorado. A database was 

compiled that includes 112,603 Fischer assays from 587 oil 

shale exploration holes. Most of the oil-yield data are from 

analyses performed by the former U.S. Bureau of Mines oil 

shale laboratory in Laramie, Wyo. with some analyses made 

by private laboratories. Location data for these 587 Utah oil 

shale drill holes are listed in a spreadsheet that is included in 

the CD–ROM.

These Utah Fischer assays and histograms are part of a 

much larger collection of oil shale information, including geophysical and lithologic logs, water data, chemical, and X-ray 

diffraction analyses on the Green River oil shale deposits in 

Utah, Colorado, and Wyoming held by the U.S. Geological 

Survey (USGS). Because of an increased interest in oil shale, 

this CD–ROM, which contains information on the Uinta Basin 

oil shale deposits in eastern Utah, is being released to the public. The Fischer assay data and oil-yield histograms from the 

Uinta Basin can be found in this chapter.

Microsoft Excel spreadsheets included with this chapter 

contain the Fischer assay data from the 587 holes, as well as 

data on the operator, drill-hole name, and well location. Histograms of the oil yields obtained from the Fischer assays are 

presented in Adobe PDF format. Fischer assay text-data files 

are also included in the CD–ROM.

For several decades, the USGS has collected core, cuttings, and other subsurface data from boreholes drilled to 

evaluate the oil shale deposits in the Eocene Green River 

Formation in the Uinta Basin of northeastern Utah and 

northwestern Colorado. In the Uinta Basin, the Green River 

Formation was deposited in Lake Uinta during early to middle 

Eocene time. Initially, Lake Uinta formed in an interior drainage basin that included both the present areas of the Uinta and 

Piceance Basins. Later, during the Long Point transgression, 

the lake expanded to cover both basins, but again became 

separate following the rise of the intervening Douglas Creek 

Arch (fig. 1; Johnson, 1985). The Long Point transgression 

marks the beginning of the deposition of the Garden Gulch, 

Parachute Creek, and Douglas Creek Members of the Green 

River Formation (fig. 2), with the richest oil shales deposited 

in the Garden Gulch and Parachute Creek Members. It was 

from this area rich in oil shale that data were collected and 

preserved for use by researchers and industry in anticipation 

of the time when Green River oil shale deposits would become 

an economically practical alternate source of fossil energy.

The types of data collected include (1) thousands of 

Fischer (oil shale) assays (American Society for Testing and 

Materials, 1980) on cores and cuttings from rotary-drilled 

holes; (2) geophysical and lithologic logs of drill holes; (3) 

chemical, water-quality, and X-ray diffraction analyses; 

as well as (4) rock mechanics data. Fischer assay data and 

histograms for 587 drill holes, of which 365 were cored, are 

included in this chapter. Plate 1 shows the general locations 

of these drill holes in northeastern Utah and northwestern 

Colorado. Each drill hole was assigned a unique 4-digit 

number preceded by “U” for Utah (for example, U0001). The 

database created for this assessment contains 112,603 samples. 

Although this data set is far from complete, it most likely 

represents the largest single source of available subsurface 

information on the Green River Formation oil shale deposits in 

northeastern Utah and northwestern Colorado.

Most of the Fischer assays on oil shale samples were 

conducted by the former U.S. Bureau of Mines (USBM) laboratory in Laramie, Wyo. (Dyni and others, 2006; Vanden Berg 

and others, 2006), with some done by private laboratories. 

From the late 1940s to the early 1980s, the USBM analyzed 

core splits and drill cuttings from holes drilled by Federal 

agencies in the Green River Formation oil shale deposits in 

Utah, Colorado, and Wyoming. A large amount of data was 

also obtained from energy companies that drilled exploratory 

holes on private or leased oil shale lands in the region. Many 

of these companies generously donated analytical data, as well 

as drill cores and cutting samples, which are being stored by 

the USGS.

CD–ROM

This chapter in the CD–ROM reports data from three 

directories: Histograms, Spatial, and Spreadsheets. The 

Histogram directory contains oil-yield histograms, in scaled 

Fischer Assay Histograms of Oil Shale Drill Cores and 

Cuttings from the Uinta Basin, Utah and Colorado

By Jesse G. Self, Michael E. Brownfield, Ronald C. Johnson, and Tracy J. Mercier
Figure 1. Geologic map of the Uinta and Piceance Basins, northeastern Utah and northwestern Colorado, showing Upper Cretaceous and 

Carbon

Cha

Daggett

Delta

Duchesne

Eagle

Emery

Garfield

Gr

Gunnison

Hinsdale

Jack

Juab

L

Mesa

Moffat

Montrose

Ouray

Pitkin

Rio Blanco

Routt

Sagu

San Juan

San Miguel

Sanpete

Sevier

Summit

Uintah

Utah

Wasatch

Wayne

Piute

Green River

Colorado River

Great Salt Lake (part)

UtahLake

Flaming GorgeReservoir (part)

15

80

70

40

40

50

70

Glenwood

Springs

Craig

Montrose

Nephi Price

Provo

Vernal

Salt Lake

City

Gunnison

Salina

Grand 

Junction

UTAH COLORADO

39°

38°

40°

41° 110° 109° 111° 112° 108° 107° 

UintaBasin

Piceance

Basin Douglas Creek archColor

0 25 50 MILES

EXPLANATION

Uinta-Piceance Province boundary

Upper Tertiary strata (undifferentiated)Quaternary strata (undifferentiated)

Green River FormationLower Tertiary/Upper Cretaceous strata (undifferentiated)

Mesaverde Group

Fault—Tick on downthrown sideGilsonite dike

Tertiary intrusive/extrusive rocks (undifferentiated)

City or town
Douglas

Base of Tertiary rocksCity or town

39 EXPLANATION

40

41

111 110 109

Location of cross section

A

A A’

A 

Index map

40302010 50 MILES

0 40 80 KILOMETERS

0

San

Rafael

swell

Precambrian rocksRocks younger than Dakota SandstoneDakota Sandstone through  Cambrian rocks

Vernal

Price

Rangely

arch

Creek

Wyoming

Colorado

Utah Uinta uplift

Uinta Basin Wasatch uplift

A’

Uinta Formation

Parachute

Creek Member

Green River

Formation

Duchesne River

Formation and

Uinta Formation

(undivided)

Uinta

Formation

Green River Formation

and North Horn

Formation (undivided)

Wasatch

Formation

Garden Gulch Member

West 

FEET 

2,0001,000

0 

0

0 10 

10 

Freshwater lacustrine and paludal rocks with molluscs and thin coal beds Dolomitic oil shale with nahcolite and halite

Variegated mudstone, sandstone, and siltstone

Illitic oil shale

Carbonate-rich marginal lacustrine mudstone with ostracodal, oolitic, and stromatolitic limestones

Volcanoclastic rocks

EXPLANATION

Unconformity

Figure 2. Tertiary stratigraphic column for the Uinta Basin, northeastern Utah and northwestern Colorado, showing the Wasatch, North Horn, Duchesne River, and Uinta Formations and associated members.
4 Fischer Assay Histograms of Oil Shale Drill Cores and Cuttings from the Uinta Basin, Utah and Colorado

Adobe PDF format (Adobe Systems, Inc., 2007), for 587 drill 

holes with Fischer assay data. The Spatial directory contains 

data for these drill holes along with 109 additional wells that 

have no analyzed samples. These 109 drill holes are included 

on plate 1. The majority of the locations were digitized using 

ArcGIS ver. 9.1 (ESRI, 2005) based on footage measurements, 

east and west of Public Land Survey System (PLSS) section 

corners contained in the original database. Source PLSS files 

used for plotting locations were obtained from the U.S. Bureau 

of Land Management (BLM) in Utah and projected to North 

American Datum 27 (NAD27). Where footage measurements 

were not available, locations were digitized as being in the 

center of the quarter-quarter section, the quarter section, or the 

center of the section, that is, the best location data available in 

the original database were used. In a minimal number of cases 

where location data in the original database were questionable, 

locations were verified using the Utah Division of Oil, Gas, 

and Mining, and the State of Colorado Oil and Gas Conservation Commission’s online databases. ASCII and Google Earth 

keyhole markup language (KML) file formats of the locations 

of the drill holes are also included in the Spatial folder. 

The Spreadsheets folder includes Microsoft EXCEL 

(Microsoft Corp., 2006) spreadsheets (UT_Oil_Shale_Assays. 

xlsx; UT_Borehole.xlsx). The UT_Borehole.xlsx spreadsheet 

contains information on 587 core and rotary holes with Fischer 

assays, and the 109 holes without analyses. The drill holes 

are sorted by the USGS’s unique 4-digit borehole number 

(U0001). The file includes well locations, operator and well 

name, surface elevation, core-hole location when known, 

depths of lithologic log units, geophysical logs that were run, 

and other data. Table 1 defines the column headers in the Utah 

reference spreadsheet. 

The Fischer assay data (Spreadsheet folder) included in 

this CD–ROM are presented in spreadsheet format (UT_Oil_ 

Shale_Assays.xlsx). The UT_Oil_Shale_Assays.xlsx spreadsheet includes the 112,603 assays from the original laboratory Fischer assay reports. In a few cases, separate analyses 

were taken from the same drill hole and these sets of data are 

following the USGS drill-hole number, whereas core holes 

the column headers in the Fischer assay data sets.

Where samples were not analyzed, the Fischer assay data 

-

gram to be created. Missing sample intervals can be detected 

in the database by the lack of a USBM laboratory number 

(LABNO, table 2) followed by “0” in all of the Fischer assay 

Oil-Yield Histograms

Oil shale-yield histograms were created for the 587 holes 

with Fischer assay data in Grapher 7 (Golden Software, Inc., 

Due to restrictions on spreadsheet size in Grapher 7 the single 

EXCEL spreadsheet (UT_Oil_Shale_Assays.xlsx) had to be 

divided into three smaller EXCEL spreadsheets (U1–U250.xls, 

U251–U450.xls, and U451–U639.xls) which are also included 

in the Spreadsheet folder on this CD–ROM. The histograms 

were created using the “Step Plot” feature in Grapher 7 using 

data from one of the three newly created spreadsheets (for 

example U1–U250.xls). Once created, the histograms (or 

step plots) were then exported in PDF(U0001.pdf) format 

and opened in Adobe Illustrator CS3, where they were scaled 

vertically to 1 in. = 50 ft and exported again in PDF format 

(U0001.pdf , 69_BB_CH_5_SUP, Histogram folder). Figure 3 is 

an example of part of the oil-yield histogram plot for a borehole 

in the Histogram folder. As with the Fischer assay data, histofollowing the USGS drill-hole number and the core holes have 

of drill holes with two separate analyses are labeled with an 

Adobe Illustrator CS3 (Adobe Systems, Inc., 2007), a few of 

the histograms created from the deeper wells had to be split 

into two parts and were labeled accordingly (for example 

U0316Rpart1.pdf and U0316Rpart2.pdf). 

If errors or omissions of data are found in this disc, 

at or Ronald C. Johnson at 

rcjohnson@usgs.gov.
Oil-Yield Histograms 5

Table 1. Names and definitions from the column headers for the Utah oil shale borehole information spreadsheet (UT_

Borehole.xlsx)

[USGS, U.S. Geological Survey; ID, identification; 3D, three dimension]

Column name Column definition

USGSID Unique ID assigned by staff geologist

OPERATOR Name of the company or agency that drilled the borehole or project name

WELLNAME Name of the borehole assigned by the company or agency that drilled it

API American Petroleum Institute ID number

ALTAPI Alternate American Petroleum Institute ID number

COUNTY Name of county in Utah 

TOWNSHIP Township 

RANGE Range

SECTION Section

QTRQTR Quarter-quarter section

MERIDIAN Principal meridian used: Salt Lake (SL) or Uinta (UN) meridian

UTME Universal Transverse Mercator easting

UTMN Universal Transverse Mercator northing

LATITUDE Latitude, in decimal degrees, North American Datum 1927, software-calculated, original record

LONGITUDE Longitude, in decimal degrees, North American Datum 1927, software-calculated, original record

EW Distance, in feet, measured east or west from section line

NS Distance, in feet, measured north or south from section line

YRDRILLED Year that the borehole was drilled

TD Total depth of the borehole, in feet

ELGRND Elevation, in feet, of ground level at borehole

ELKELBUSH Elevation, in feet, of Kelly bushing at borehole

ELDRLFRM Elevation, in feet, of drill platform

CORETOP Depths, in feet, of top of the interval that was cored in the borehole

COREBOT Depths, in feet, of bottom of the interval that was cored in the borehole

CORELOC Physical location of the core from core hole, for example, USGS Core Research Center

CUTTOP Depths, in feet, of top of the interval that cuttings were collected from the borehole

CUTBOT Depths, in feet, of bottom of the interval that cuttings were collected from the borehole

CUTLOC Physical location of the cuttings from core hole, for example, USGS Core Research Center

FISCHTOP Depths, in feet, of top of the sequence analyzed by Fischer assays

FISCHBOT Depths, in feet, of bottom of the sequence analyzed by Fischer assays

TOTASSAYS Number of Fischer assays that were made

NUMGT25 Number of Fischer assay samples with greater than 25 gallons per ton

ASSAYLAB Name of laboratory where Fischer assays were performed

LITHLOGTOP Depths, in feet, of top of the sequence of core or rotary cuttings for which a lithologic log was prepared

LITHLOGBOT Depths, in feet, of bottom of the sequence of core or rotary cuttings for which a lithologic log was prepared

LOGLOC Location of Geophysical logs

DENSTOP Depths, in feet, of top of the density log of borehole

DENSBOT Depths, in feet, of bottom of the density log of borehole

NEUTTOP Depths, in feet, of top of the neutron log of borehole

NEUTBOT Depths, in feet, of bottom of the neutron log of borehole

SONICTOP Depths, in feet, of top of the sonic log of borehole

SONICBOT Depths, in feet, of bottom of the sonic log of borehole
6 Fischer Assay Histograms of Oil Shale Drill Cores and Cuttings from the Uinta Basin, Utah and Colorado

Table 1. Names and definitions from the column headers for the Utah oil shale borehole information spreadsheet (UT_

Borehole.xlsx).—Continued

[USGS, U.S. Geological Survey; ID, identification; 3D, three dimension]

Column name Column definition

ELECBOT Depths, in feet, of bottom of the electric log of borehole

GAMMATOP Depths, in feet, of top of the gamma ray log of borehole

GAMMABOT Depths, in feet, of bottom of the gamma ray log of borehole

CALIPTOP Depths, in feet, of top of the caliper log of borehole

CALIPBOT Depths, in feet, of bottom of the caliper log of borehole

TEMPTOP Depths, in feet, of top of the temperature log of borehole

TEMPBOT Depths, in feet, of bottom of the temperature log of borehole

CEMENTTOP Depths, in feet, of top of the cemented interval of borehole

CEMENTBOT Depths, in feet, of bottom of the cemented interval of borehole

3DVELTOP Depths, in feet, of top of the 3D velocity log of borehole

3DVELBOT Depths, in feet, of bottom of the 3D velocity log of borehole

ELASTTOP Depths, in feet, of top of the elastic properties log of borehole

ELASTBOT Depths, in feet, of bottom of the elastic properties log of borehole

COMPROTOP Depths, in feet, of top of the compensated density log of borehole

COMPROBOT Depths, in feet, of bottom of the compensated density log of borehole

SPINTOP Depths, in feet, of top of the spontaneous potential and conductivity log of borehole

SPINBOT Depths, in feet, of bottom of the spontaneous potential and conductivity log of borehole

RADTRCTOP Depths, in feet, of top of the radioactive tracer log of borehole

RADTRCBOT Depths, in feet, of bottom of the radioactive tracer log of borehole

LOGLOC2 Location of geophysical logs

Table 2. Names and definitions for the column headers for the Fischer assay data spreadsheet 

(UT_Oil_Shale_Assays.xlsx).

[USGS, U.S. Geological Survey; Wyo.,Wyoming; ID, identification]

Column name Column definition

LABNO U.S. Bureau of Mines, Laramie, Wyo., laboratory number

TOPFT Depth, in feet, measured from surface datum to top of sampled interval

BOTFT Depth, in feet, measured from surface datum to base of sampled interval

SHLOILPCT Amount of shale oil, in weight percent

WATERPCT Amount of water, in weight percent

SHLRSDPCT Amount of shale residue, in weight percent

GASPLSPCT Amount of “gas plus loss,” in weight percent

OILGPT Oil yield, in U.S. gallons per short ton of rock

WTRGPT Water, in U.S. gallons per short ton of rock

SPCFGRAV Specific gravity of shale oil

COKETEND Tendency for spent shale to coke

USGSID Unique drill-hole number assigned by the USGS
0 20 40 60 80 100

0 20 40 60 80 100

0

U0020

Byllesby, Inc.

Windy

sec. 24, T. 12 S., R. 20 E.

OIL YIELD, IN GALLONS PER TON

OIL YIELD, IN GALLONS PER TON

300

200

100

USGS number

Operator

Well name

Location (section, township, range)

Oil-yield histogram—In gallons per ton

EXPLANATION

U0020

Byllesby, Inc.

Windy

sec. 24, T. 12 S., R. 20 E.

Parachute Creek Member (part)

Green River Formation (part)

0

50

100 FEET

Scale

Figure 3. Part of the histogram plot showing Fischer assay oil-yield data, in gallons per ton, for borehole U0020; with sampling 

from the Parachute Creek Member of the Green River Formation in the Uinta Basin, northeastern Utah and northwestern 

Colorado.

Oil-Yield Histograms 7
8 Fischer Assay Histograms of Oil Shale Drill Cores and Cuttings from the Uinta Basin, Utah and Colorado

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References Cited

Adobe Systems, Inc., 2007, Adobe Design Premium CS3, San 

Jose, Calif.

American Society for Testing and Materials, 1980, Standard method of test for oil from oil shale: Annual Book 

of ASTM Standards, Part 25, Designation D 3904-80, p. 

513–515.

Dyni, J.R., Donnell, J.R., Vanden Berg, M.D., and Tabet, D.E., 

2006, Preliminary Utah oil shale database: U.S. Geological 

Survey Open-File Report OF-2006–1295, CD–ROM.

ESRI (Environmental Systems Research Institute), 2005, 

ArcGIS ver. 9.1, Redlands, Calif.

Golden Software, Incorporated, 2007, Grapher 7.

Johnson, R.C., 1985, Early Cenozoic history of the Uinta and 

Piceance Creek Basins, Utah and Colorado, with special 

reference to the development of Eocene Lake Uinta United 

States: Rocky Mountain Section, Society of Economic 

Paleontologists and Mineralogists: Denver, Colo., 

p. 247–276.

Microsoft Corporation, 2006, Microsoft Access and Excel 

(part of Microsoft Office 2007).

Vanden Berg, M.D., Dyni, J.R., and Tabet, D.E., 2006, Utah 

oil shale database: Utah Geological Survey Open-File 

Report 469, CD–ROM.